The present invention relates to a dust-proof, scratch-resistant film. More particularly, the present invention relates to a transparent film that is excellent in prevention of soiling created by deposition of dust, on the surface of various displays of word processors, computers, and televisions, surfaces of polarizing plates used in liquid crystal displays, optical lenses, such as sunglass lenses of transparent plastics, lenses of eyeglasses, finder lenses for cameras, covers for various instruments, and surfaces of window glasses of automobiles and electric rail cars, and at the same time possesses excellent scratch resistance.
Glass plates and transparent resin plates, such as transparent plastic plates, are used in curve mirrors, back mirrors, goggles, and window glasses, particularly displays of electronic equipment, such as personal computers and word processors, and other various commercial displays. These resin plates, as compared with the glass plates, are lightweight and less likely to be broken, but on the other hand, they are disadvantageous in that dust is electrostatically deposited on the surface thereof and, in addition, the hardness is so low that the scratch resistance is poor and, hence, a scratch is created deteriorating the transparency.
Conventional methods for preventing the electrostatic deposition of dust and the deterioration in transparency created by scratching upon being rubbed include coating of an antistatic paint on the surface of the plastic and formation of a hard coat on the surface of the plastic.
The hard coat with a conductive material, such as an antistatic agent, being dispersed in an amount large enough to prevent the deposition of foreign materials, however, has unsatisfactory transparency and is further disadvantageous in that curing is inhibited making it impossible to provide hardness high enough to meet the scratch resistance requirement.
A highly transparent conductive thin film can be formed by vapor deposition of a metal oxide or the like. The process of vapor deposition, however, is inefficient to cause increased cost and has an additional disadvantage that the scratch resistance of the formed thin film is unsatisfactory.
Accordingly, an object of the present invention is to provide an antistatic hard coat film that, when used in various displays for observing visual information, such as an object, a letter, or a figure, through a transparent substrate, or used in mirrors for observing an image from a reflective layer through a transparent substrate, can prevent electrostatic deposition of foreign materials on the surface of the transparent substrate and at the same time has hardness high enough not to cause a deterioration in transparency due to a scratch or the like upon being rubbed.
The hard coat film according to the present invention can maintain the transparency on such a level as will not cause a problem associated with the perception of an image seen through the film.
In order to solve the above problems, the present invention provides an antistatic hard coat film comprising: a transparent substrate film; a transparent conductive layer provided on the substrate film; and a hard coat layer provided on the transparent conductive layer.
According to a preferred embodiment of the present invention, the transparent conductive layer has a surface resistivity of not more than 1012 xcexa9/xe2x96xa1.
Further, according to a preferred embodiment of the present invention, the hard coat layer has a volume resistivity in the thickness direction of not more than 108 xcexa9xc2x7cm.
According to another preferred embodiment of the present invention, the hard coat layer comprises a reaction-curing resin composition and has a thickness of 1 to 50 xcexcm.
Further, according to another preferred embodiment of the present invention, the hard coat layer comprises an anisotropic conductive hard coat layer having a higher volume resistivity in the layer surface direction and a lower volume resistivity in the layer thickness direction.
Preferably, the anisotropic conductive layer comprises a hard coat resin comprising conductive fine particles, the diameter of the conductive fine particles being not less than one-third of the coating thickness of the anisotropic conductive layer.
Further, preferably, the conductive fine particles are particles which have been surface treated with gold and/or nickel.